Various techniques have been developed to improve the security of information accessible via computer networks. Various protocols for cryptographically protected communications sessions, for instance, provide mechanisms to ensure the confidentiality and/or integrity of data passing between two devices on a network. At the same time, computer systems themselves have become more sophisticated. A distributed computer system, for instance, may comprise multiple individual computer systems that communicate over a network, each playing a particular role in the distributed computer system. Moreover, services provided by distributed computer systems can involve complex orchestration among multiple individual computer systems. While many conventional protocols for cryptographically protected communications sessions provide high levels of security between pairs of computer systems, their use in such distributed computer systems can be highly complex and cumbersome to manage due to the number of computer systems involved.